Have you noticed most games are a bit graphically inferior, and the audio is mainly 3 channel chip tunes? Most games were definitely better on the Amiga, but there are some that were much better on the Amiga... as has been explored in another thread here. Captain Blood being the best example.
The thing that did instantly strike me when I returned to the ST was the old style borders around screens. I had got so use to the Amiga's overscan screenmodes with no borders at all that I had forgotten the ST had them in most games.